Effects of full-fat high-oleic soybean meal in layer diets on nutrient digestibility and egg quality parameters of a white laying hen strain

Authors: MAHARJAN, PRAMIR - Tennessee State University; RAHIMI, AMIN - Mountaire Farms, Inc; HARDING, KARI - North Carolina State University; Vu, Thien; MALHEIROS, RAMON - North Carolina State University; OVIEDO, EDGAR - North Carolina State University; Mian, Rouf; JOSEPH, MICHAEL - North Carolina State University; Dean, Lisa; ANDERSON, KENNETH - North Carolina State University; Toomer, Ondulla

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2023
Publication Date: 2/2/2023
Citation: Maharjan, P., Rahimi, A., Harding, K.L., Vu, T.C., Malheiros, R., Oviedo, E.R., Mian, R.M., Joseph, M., Dean, L.L., Anderson, K.E., Toomer, O.T. 2023. Effects of full-fat high-oleic soybean meal in layer diets on nutrient digestibility and egg quality parameters of a white laying hen strain. Poultry Science. 102:102486. https://doi.org/10.1016/j.psj.2023.102486.
DOI: https://doi.org/10.1016/j.psj.2023.102486

Interpretive Summary: Poultry feeding studies have demonstrated the effective utilization of full-fat soybean meal prepared from whole ‘normal-oleic’ soybeans without adverse effects on poultry growth performance. However, no studies to date have been conducted to determine the effects of full-fat ‘high-oleic soybean meal on poultry growth performance. Therefore, a poultry feeding study was conducted utilizing full-fat high-oleic soybean meal in egg producing hens to determine the effects on hen growth, bone strength, egg quality and egg fatty acid composition. Forty-eight layers were randomly assigned to one of four dietary treatments and fed the following diets for 3 weeks: (1) 1% fat- defatted control corn/soy diet, (2) 2% fat-defatted corn/soy diet, (3) full-fat normal-oleic soybean meal + corn diet, and (4) full-fat high-oleic soybean meal + corn diet. Nutrient digestibility (crude fat and crude protein) was analyzed at termination of the study with feed samples and intestinal contents. Bones samples from the tibia were collected for bone strength analysis, and shell eggs were collected to determine eggshell quality and chemistry. Nutrient digestibility and eggshell quality parameters (shell mass, shell color, shell strength, yolk color, egg white composition) were not different between the dietary treatments. However, eggs produced from hens fed the full-fat high-oleic soybean meal had significantly higher amounts of monounsaturated oleic fatty acid in the eggs produced compared to the other dietary treatment groups. These findings suggest that high-oleic soybean meal in the diets of poultry may nutritionally enrich the poultry products produced.

Technical Abstract: This study was conducted to understand the impact of including full fat high-oleic soybean meal in layer hen diets on nutrient digestibility and added nutritional value in eggs. Forty-eight layers (~36 wk old) were randomly assigned to one of 4 isonitrogenous (18.5% crude protein) treatment diets with 12 replicate birds per treatment in a 3-wk study. Treatments were 1) solvent extracted defatted soybean meal + corn diet, 2) dry extruded defatted soybean meal + corn, 3) full-fat soybean meal + corn, 4) high-oleic full-fat soybean meal + corn diet. Apparent ileal digestibility of crude fat (CF) and crude protein (CP) were determined using celite (~2%) as an indigestible marker. Tibia strength and egg quality parameters (egg weight, shell strength, Haugh unit, shell color, and yolk color) were recorded during the study. Fatty acid profiles, including the monounsaturated fatty acid, oleic acid (C18:1, cis), in eggs and adipogenic tissue (liver, muscle, and fat pad) were measured using gas chromatography (GC-FID). Digestibility values of CF ranged from 71 to 84% and CP varied from 67 to 72% for treatment diets, with treatment mean values being no different (P > 0.05) between treatment diets. No differences between treatment diets in tibia strength or egg quality parameters (egg weight, shell strength, and Haugh unit) were observed (P > 0.05) except for yolk color. Similarly, there were no differences in the total lipids in egg yolk (P > 0.05) between treatment diets. However, oleic acid percentage of total lipid in egg and tissue was significantly higher (P < 0.001) in hens given the high-oleic full-fat soybean meal diet than in other treatment groups. No difference was observed in oleic acid percentage of total lipid in egg between the other 3 treatment diets (P > 0.05). Overall, the results exhibited that the eggs and tissue of layer hens fed the full-fat high-oleic acid soybean meal diet were higher in oleic acid while the CF and CP digestibility remained similar to the digestibility of the other diets.